Effect of transition metals (Nb, Ta, and V) doping on the high-temperature mechanical and tribological properties of CrYN coatings

This study focused on developing a high-temperature tribological coating for AISI 316L stainless steel. CrYN coatings doped with transition metals such as niobium, tantalum, and vanadium (Me-CrYN) were deposited using a closed-field unbalanced magnetron sputtering (CFUBMS) system. In a previous study, the Taguchi L9 orthogonal array design was employed to optimize the deposition parameters based on tribological performance under dry sliding conditions at room temperature. Among the nine experimental runs, the three coatings exhibiting the lowest friction coefficients and highest wear resistance were selected for high-temperature tribological testing. In the present work, these three optimized Me-CrYN coatings were systematically evaluated for their tribological and adhesion properties at elevated temperatures. High-temperature tribological performance was assessed using a pin-on-disc tribometer in ambient air at 450 °C, 550 °C, and 650 °C, with particular attention given to their frictional behavior. Additionally, adhesion strength was evaluated at room temperature via scratch testing, both on the as-deposited coatings and those subjected to high-temperature tribological testing at 450 °C, 550 °C, and 650 °C. The results demonstrate that the Me-CrYN coatings maintain tribomechanical stability at elevated temperatures, with hardness values ranging from 8.8 to 15.3 GPa. Nb-doped coatings exhibited a reduction in friction from ∼0.55 at room temperature to ∼0.30 at 650 °C (≈45 % decrease), while Ta-doped coatings maintained stable values around 0.40 across all temperatures (<5 % variation). In contrast, V-doped coatings showed an initial rise from ∼0.13 at room temperature to ∼0.30 at 450 °C (≈115 % increase), but then decreased to ∼0.10 at 550 °C (≈25 % below RT) and ∼0.12 at 650 °C (≈10 % below RT). Adhesion strength was preserved after thermal exposure, supporting their potential for high-temperature applications

Nb-doped hydrogenated diamond-like carbon coated biodiesel injectors material: Synthesis, structure and properties

Despite the economic and environmental benefits of biodiesel, it poses significant challenges, including coking on metal surface and increased wear on diesel engine injector nozzles. Therefore, this study investigates the synthesis of niobium-doped diamond-like carbon (Nb-DLC) coatings on two types of injector nozzle materials (viz. H13 steel, AISI 420 stainless steel) using the Closed-Field Unbalanced Magnetron Sputtering (CFUBMS) technique. Comprehensive characterizations, including microstructural analysis, crystal structure evaluation, hardness assessment, and tribological property assessment, were conducted. The Nb-DLC coatings demonstrated a stable friction coefficient, with values four times lower than that of the substrate materials. The present findings demonstrate significant enhancements in terms of structural composition, crystalline phase, hardness, friction coefficients, and adhesion properties due to the Nb-DLC coatings. Therefore, Nb-DLC coated materials could be the promising candidate material for biodiesel engine injector nozzle applications. This emphasizes their potential to contribute significantly to the sustainable consolidation of biodiesel within automotive engine

The Türki̇ye earthquake sequence of February 2023: A longitudinal study report by EEFIT

On 6 February 2023 at 4:17 am local time, a large area in southeastern Türkiye and northern Syria was hit by an Mw 7.8 earthquake, which was followed by an Mw 7.5 earthquake at 1:24 pm local time, causing the loss of more than 50,000 lives, some 100,000 injuries and significant damage to buildings and infrastructure, estimated to be in the range of 84.1 billion USD for Türkiye alone. The largest earthquake in Türkiye since the deadly 1939 Erzincan earthquake with however much larger losses, the sequence immediately attracted the attention of the global post-disaster reconnaissance/engineering communities. This included the Earthquake Engineering Field Investigation Team (EEFIT), who, within one week of the event, gathered a team with 30 people from academia and industry in the UK (19), Türkiye (5), New Zealand (1), Hungary (1), Bulgaria (1), Greece (1) and USA (1) with two support members from the UK and the Netherlands, to study the events and their impacts, and also to develop suggestions to reduce the existing vulnerabilities in the future. The team was organised in the form of 6 working groups as shown below, which were (1) strong ground motions and seismotectonics, (2) geotechnics, (3) structures, (4) infrastructure, (5) remote sensing and (6) relief response and recovery

Effect of bleaching on sound enamel and with early artificial caries lesions using confocal laser microscopy

The aim of this study was to evaluate effect of bleaching agents on sound enamel (SE) and enamel with early artificial caries lesions (CL) using confocal laser scanning microscopy (CLSM). Eighty blocks (4 × 5 × 5 mm) of bovine enamel were used and half of them were submitted to a pH cycling model to induce CL. Eight experimental groups were obtained from the treatments and mineralization level of the enamel (SE or CL) (n=10). SE groups: G1 - unbleached (control); G2 - 4% hydrogen peroxide (4 HP); G3 - 4 HP containing 0.05% Ca (Ca); G4 - 7.5% hydrogen peroxide (7.5 HP) containing amorphous calcium phosphate (ACP). CL groups: G5 - unbleached; G6 - 4 HP; G7 - 4 HP containing Ca; G8 - 7.5 HP ACP. G2, G3, G6, G7 were treated with the bleaching agents for 8 h/day during 14 days, while G4 and G8 were exposed to the bleaching agents for 30 min twice a day during 14 days. The enamel blocks were stained with 0.1 mM rhodamine B solution and the demineralization was quantified using fluorescence intensity detected by CLSM. Data were analyzed using ANOVA and Fisher's tests (α=0.05). For the SE groups, the bleaching treatments increased significantly the demineralization area when compared with the unbleached group. In the CL groups, no statistically significant difference was observed (p>0.05). The addition of ACP or Ca in the composition of the whitening products did not overcome the effects caused by bleaching treatments on SE and neither was able to promote remineralization of CL.Department of Restorative Dentistry UNOPAR - University of North Paraná, Londrina, PRDepartment of Restorative Dentistry Dental School University of Illinois at Chicago, Chicago, ILDepartment of Dental Materials and Prosthodontics Araçatuba Dental School Universidade Estadual Paulista (UNESP), Araçatuba, SPDepartment of Restorative Dentistry Piracicaba Dental School UNICAMP - University of Campinas, Piracicaba, SPDepartment of Dental Materials and Prosthodontics Araçatuba Dental School Universidade Estadual Paulista (UNESP), Araçatuba, S

Method to obtain platelet-rich plasma from rabbits (Oryctolagus cuniculus )

Abstract: Platelet-rich plasma (PRP) is a product easy and inxpesnsive, and stands out to for its growth factors in tissue repair. To obtain PRP, centrifugation of whole blood is made with specific time and gravitational forces. Thus, the present work aimed to study a method of double centrifugation to obtain PRP in order to evaluate the effective increase of platelet concentration in the final product, the preparation of PRP gel, and to optimize preparation time of the final sample. Fifteen female White New Zealand rabbits underwent blood sampling for the preparation of PRP. Samples were separated in two sterile tubes containing sodium citrate. Tubes were submitted to the double centrifugation protocol, with lid closed and 1600 revolutions per minute (rpm) for 10 minutes, resulting in the separation of red blood cells, plasma with platelets and leucocytes. After were opened and plasma was pipetted and transferred into another sterile tube. Plasma was centrifuged again at 2000rpm for 10 minutes; as a result it was split into two parts: on the top, consisting of platelet-poor plasma (PPP) and at the bottom of the platelet button. Part of the PPP was discarded so that only 1ml remained in the tube along with the platelet button. This material was gently agitated to promote platelets resuspension and activated when added 0.3ml of calcium gluconate, resulting in PRP gel. Double centrifugation protocol was able to make platelet concentration 3 times higher in relation to the initial blood sample. The volume of calcium gluconate used for platelet activation was 0.3ml, and was sufficient to coagulate the sample. Coagulation time ranged from 8 to 20 minutes, with an average of 17.6 minutes. Therefore, time of blood centrifugation until to obtain PRP gel took only 40 minutes. It was concluded that PRP was successfully obtained by double centrifugation protocol, which is able to increase the platelet concentration in the sample compared with whole blood, allowing its use in surgical procedures. Furthermore, the preparation time is appropriate to obtain PRP in just 40 minutes, and calcium gluconate is able to promote the activation of platelets

Varying patterns of protein synthesis in bread wheat during heat shock

High temperatures during seedling growth are considered as one of the factors that can modify surviving properties in wheat (Triticum aestivum L.) plant. This work attempts to evaluate the heat shock responses of seedling of winter wheat (Bezostaya-1) using growth parameters (seedling length, embryonal root length and embryonal root number), membrane stability index (MSI) and two dimensional (2D) gel electrophoresis analysis of heat shock proteins (HSPs) during heat shock. Seedlings grown until first leaf opening at controlled conditions (23 degrees C, 200 mu mol m(-2) s(-1), 16h day/8h night, 50-60% humidity) were exposed to 37 degrees C or 45 degrees C high temperatures for 2, 4 and 8 hours. While 37 degrees C did not cause any significant change, 45 T heat treatments caused significant decrease in terms of seedling and root length, and leaf MSI for all exposure times. However, all the plants from 45 degrees C heat treatments continued to grow during recovery period. 2D protein analysis indicated that 37 degrees C, 8 hours exposure caused stronger and more diverse heat shock response than the other treatments, followed by 37 degrees C, 4 hours, 45 degrees C, 8 hours, 45 degrees C, 4 hours, 45 degrees C, 2 hours treatments. 5 protein spots, ranging from 6-7.8 pI (isoelectric point) and 27-31.7 kDA molecular weight, were expressed at 37 degrees C, 2 hours and continued at 37 and 45 degrees C for all exposure times. This suggests that these early proteins and other newly synthesized proteins may have protective effects at 37 and 45 degrees C and provide plants for healthy growth during the recovery period

Varying patterns of protein synthesis in bread wheat during heat shock

High temperatures during seedling growth are considered as one of the factors that can modify surviving properties in wheat ( Triticum aestivum L.) plant. This work attempts to evaluate the heat shock responses of seedling of winter wheat (Bezostaya-1) using growth parameters (seedling length, embryonal root length and embryonal root number), membrane stability index (MSI) and two dimensional (2D) gel electrophoresis analysis of heat shock proteins (HSPs) during heat shock. Seedlings grown until first leaf opening at controlled conditions (23 °C, 200 μmol m −2 s −1 , 16h day/8h night, 50–60% humidity) were exposed to 37 °C or 45 °C high temperatures for 2, 4 and 8 hours. While 37 °C did not cause any significant change, 45 °C heat treatments caused significant decrease in terms of seedling and root length, and leaf MSI for all exposure times. However, all the plants from 45 °C heat treatments continued to grow during recovery period. 2D protein analysis indicated that 37 °C, 8 hours exposure caused stronger and more diverse heat shock response than the other treatments, followed by 37 °C, 4 hours, 45 °C, 8 hours, 45 °C, 4 hours, 45 °C, 2 hours treatments. 5 protein spots, ranging from 6–7.8 p I (isoelectric point) and 27–31.7 kDA molecular weight, were expressed at 37 °C, 2 hours and continued at 37 and 45 °C for all exposure times. This suggests that these early proteins and other newly synthesized proteins may have protective effects at 37 and 45 °C and provide plants for healthy growth during the recovery period

Papillon-Lefevre syndrome. Analysis of neutrophil chemotaxis

PAPILLON-LEFEVRE SYNDROME (PLS) IS DESCRIBED as the association of palmar-plantar hyperkeratosis with precocious periodontal disease which results in exfoliation of primary and permanent dentitions. This study was planned to assess the chemotaxis of peripheral blood neutrophils in 7 patients (3 females and 4 males) with Papillon-Lefevre syndrome. The neutrophil chemotaxis was analyzed using the zymosan activated serum (ZAS) assay. Chemotaxis and spontaneous migration measurements were compared to those of the healthy control subjects. The peripheral blood neutrophil chemotaxis and spontaneous migration were depressed in all patients with Papillon-Lefevre syndrome. The decreased chemotaxis of peripheral blood neutrophils strongly suggests that the neutrophils may act as one of the important key determinants in the pathogenesis of severe periodontal destruction in patients with PLS